Structure and thermal stability of fully oxidized TiO2/Pt(111) polymorphs

► We study fully oxidized TiO2/Pt(111) films of various thickness θ by STM and LEED. ► θ < 10 ML: the film structure is the TiO2(B) polymorph, with highly defective islands. ► θ > 10 ML: STM shows the quasi-(1 × 2) rutile-like incommensurate unit cell. ► A new (7 × 1) periodicity on the islands is observed, maintained even at θ > 20 ML.